1. Field of the Invention
This invention relates to a cover device for use with a casing to form a battery housing for a storage battery, more particularly to a cover device which prevents electrolyte received in each of the cell compartments of the casing from flowing into the adjacent cell compartments when the battery housing is accidentally toppled over.
2. Description of the Related Art
Referring to FIG. 1, a conventional battery housing for a storage battery generally includes a hollow casing 1, and a cover device 2 mounted on the casing 1. The casing 1 opens upwardly, and confines a rectangular interior 11 which is divided by a number of partition plates 12 into a plurality of cell compartments 13 for receiving electrolyte and plate electrodes. As shown in FIGS. 1 and 2, the cover device 2 includes a lower cover body 20 which has a top wall and a surrounding wall that extends downwardly from the periphery of the top wall and that confines a cavity 21. The cavity 21 is also divided into a plurality of chambers 23 aligned respectively with the cell compartments 13 by means of a number of dividers 22 that are aligned respectively with the partition plates 12. Each of the dividers 22 has a bottom edge which is in contact with a top edge of a respective one of the partition plates 12 and which is formed with a notch 24. The top wall is further formed with a pair of openings 26 to permit extension of electrical wires therethrough. The openings 26 are sealed after installing the electrical wires.
The top wall of the lower cover body 20 is divided into an electrolyte pouring area 25 and a vent area 26. The electrolyte pouring area 25 is provided with a plurality of electrolyte pouring tubes 251 which extend into the chambers 23, respectively. The vent area 26 is provided with a vent tube 262 that confines a vent hole communicated with one of the chambers 23. The vent tube 262 has a top edge formed with a pair of notches 263. A pressure cap 264 is mounted movably on the vent tube 262 for covering the vent hole and the notches 263. Vapor that is generated in the cell compartments 13 during use of the storage battery flows through the notches 24 and into the vent hole to push the pressure cap 264 upwardly so as to expose the notches 263 for venting the vapor from the cell compartments 13. An upper cover plate 27 is sealed to the vent area 26 on the top side of the top wall of the lower cover body 20, and confines a space with the vent area 26. The top wall of the lower cover body 20 is further formed with a pair of slits 261 communicated with the space. As such, the vapor which is vented from the cell compartments 13 via the vent hole and the notches 263 can escape from the cover device 2 via the slits 261.
The above-described cover device 2 provides a sealing effect to prevent leakage of the electrolyte from the battery housing, and permits venting of the vapor generated during use of the storage battery. However, since only one vent hole is provided in the cover device 2, the venting effect achieved thereby is insufficient. In addition, when the battery housing is accidentally toppled over, the electrolyte received in each of the cell compartments 13 is likely to flow through the notches 24, as shown in FIG. 3, to result in uneven distribution of the electrolyte among the cell compartments 13, thereby adversely affecting the performance of the storage battery.